There's many SEO services you can buy but you need to work with legitimate businesses who provide SEO Reports on a monthly basis. SEO takes months if not years...anyone who tells you otherwise is lying to you and will take your hard earned money. I've had so many clients come to me who've had horrible experiences with SEO companies or individuals or even had their site spammed to the point where their business was in jeopardy due to black-hat link-building.
Always do you research on a good company, Google reviews or Facebook reviews are a start and ask for referrals.
From my own experience running http://www.njseos.com/